It's a really well-made puzzle game. Not sure how you did it, but the way the gameplay mechanics grow onto you is really cool. It becomes pretty natural once you get used to it, which really reminds me of the "Now you're thinking with portals" thing. Except, blue squares, I guess. Your biggest hurdle will probably be to make players understand how the mechanics work. I think once they're "in the flow", they'll like it.
Definitely a demo I'll keep on my desktop for a while, at the very least until I've cleared all the levels.
Only technical issue I found is that the game crashed when I tried to exit with escape during the game.